update docs

Author: AntonOresten

docs/src/index.md

@@ -6,9 +6,31 @@ CurrentModule = BitPacking
 
 Documentation for [BitPacking](https://github.com/MurrellGroup/BitPacking.jl).
 
-```@index
+## Contents
+
+```@contents
+Pages = ["index.md"]
+```
+
+## `bitwidth` interface for narrow types
+
+```@docs
+bitwidth
 ```
 
-```@autodocs
-Modules = [BitPacking]
+## BitPackedArray
+
+```@docs
+BitPackedArray
+bitpacked
+bitunpacked
+```
+
+## Primitives
+
+```@docs
+packbits!
+packbits
+unpackbits!
+unpackbits
 ```

src/BitPackedArray.jl

@@ -57,7 +57,7 @@ A wrapper for an array of packed bytes.
 Use [`bitpacked`](@ref) to create a `BitPackedArray`, and [`bitunpacked`](@ref) to unpack it.
 
 !!! warning
-    BitPackedArray has limited indexing support.
+    Attempting to index into a `BitPackedArray` on GPUs may lead to scalar indexing errors.
 """
 BitPackedArray